Visitor
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2 Messages
Modem has repeated disconnects & high ping - T3 timeouts & SYNC errors
I recently moved into a new home and purchased my own modem/router for the internet service. I've been going on two weeks now of random disconnects/high packet loss across my entire network; it affects all my devices including my desktop computer (via ethernet), as well as my phone and tablet over wi-fi. I changed the location of the modem and router from in my office to out in my living room, as well as out at the "box" in my garage where the service comes in. My first modem, a Netgear CM3000, had a status light stating poor downstream power, so I removed the splitter in the box in my garage. I continued to have issues.
Yesterday, I had a technician make a site visit, and he confirmed at the time that I had "strong" downstream signal of about 12-13 dbm. He told me that I needed to use the splitter to lower the signal to my modem, and he replaced it. The issue seemed to be solved so he left. Last night the issues returned. This morning, I went to the store and bought an Arris S34 modem, and tried that. I am getting the same errors in that modem as I did the CM3000, and I continue to get them at different points in my home, so I believe the issue is upstream. However, the automated troubleshooting system did not detect any errors (which by the way, I was quite frustrated when I received 3 text messages and a phone call asking me to cancel my appointment because the system said my network was fine. It was not.)
Below are my modem logs; I have already removed personal data by changing my MAC to "PERSONAL MAC". These logs are from my modem being installed in my office with a direct ethernet connection to my desktop computer. This period of time I had multiple time-outs while watching Twitch.tv, and replicated the results when I had been playing an online game and kept getting disconnected.
| 08/30/2025 19:45:57 | Notice |
CM-STATUS message sent. Event Type Code: 5; Chan ID: 28; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
|
| 08/30/2025 19:45:34 | Critical | SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:44:36 | Notice |
CM-STATUS message sent. Event Type Code: 24; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
|
| 08/30/2025 19:42:33 | Notice |
CM-STATUS message sent. Event Type Code: 5; Chan ID: 4; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
|
| 08/30/2025 19:42:30 | Critical | SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:42:30 | Critical | No Ranging Response received - T3 time-out;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:42:21 | Notice |
CM-STATUS message sent. Event Type Code: 16; Chan ID: 194; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
|
| 08/30/2025 19:42:18 | Critical | SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:42:04 | Notice |
CM-STATUS message sent. Event Type Code: 5; Chan ID: 16; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
|
| 08/30/2025 19:41:32 | Warning | RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:41:19 | Notice |
CM-STATUS message sent. Event Type Code: 16; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
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| 08/30/2025 19:41:17 | Critical | SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:41:15 | Notice |
CM-STATUS message sent. Event Type Code: 2; Chan ID: 20; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
|
| 08/30/2025 19:41:14 | Critical | SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:40:22 | Notice | US profile assignment change. US Chan ID: 41; Previous Profile: 10; New Profile: 12.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:38:10 | Notice |
CM-STATUS message sent. Event Type Code: 5; Chan ID: 16; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
|
| 08/30/2025 19:37:37 | Notice | US profile assignment change. US Chan ID: 41; Previous Profile: 11; New Profile: 10.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:37:27 | Notice |
CM-STATUS message sent. Event Type Code: 5; Chan ID: 25; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
|
| 08/30/2025 19:37:07 | Critical | SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:35:37 | Notice |
CM-STATUS message sent. Event Type Code: 5; Chan ID: 7; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
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| 08/30/2025 19:35:32 | Critical | SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:34:34 | Notice |
CM-STATUS message sent. Event Type Code: 24; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
|
| 08/30/2025 19:34:07 | Notice | US profile assignment change. US Chan ID: 41; Previous Profile: 12; New Profile: 11.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| 08/30/2025 19:34:06 | Notice |
CM-STATUS message sent. Event Type Code: 5; Chan ID: 1; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1;
|
| 08/30/2025 19:27:37 | Notice | US profile assignment change. US Chan ID: 41; Previous Profile: 10; New Profile: 12.;CM-MAC=<PERSONAL MAC>;CMTS-MAC=<PERSONAL MAC-2>;CM-QOS=1.1;CM-VER=3.1; |
| Startup Procedure | ||
|---|---|---|
| Procedure | Status | Comment |
| Acquire Downstream Channel | 405000000 Hz | Locked |
| Connectivity State | OK | Operational |
| Boot State | OK | Operational |
| Configuration File | OK | |
| Security | Enabled | BPI+ |
| DOCSIS Network Access Enabled | Allowed | |
| Downstream Bonded Channels | |||||||
|---|---|---|---|---|---|---|---|
| Channel ID | Lock Status | Modulation | Frequency | Power | SNR/MER | Corrected | Uncorrectables |
| 4 | Locked | 256QAM | 405000000 Hz | 7.9 dBmV | 43.4 dB | 12 | 30 |
| 12 | Locked | 256QAM | 453000000 Hz | 8.9 dBmV | 43.4 dB | 48 | 58 |
| 20 | Locked | 256QAM | 501000000 Hz | 8.7 dBmV | 43.4 dB | 266 | 1324 |
| 28 | Locked | 256QAM | 549000000 Hz | 7.2 dBmV | 40.4 dB | 369 | 2344 |
| 1 | Locked | 256QAM | 387000000 Hz | 7.5 dBmV | 40.9 dB | 317 | 360 |
| 2 | Locked | 256QAM | 393000000 Hz | 7.7 dBmV | 40.9 dB | 322 | 342 |
| 3 | Locked | 256QAM | 399000000 Hz | 7.6 dBmV | 40.9 dB | 278 | 428 |
| 5 | Locked | 256QAM | 411000000 Hz | 8.0 dBmV | 44.6 dB | 397 | 1372 |
| 6 | Locked | 256QAM | 417000000 Hz | 8.0 dBmV | 44.6 dB | 337 | 326 |
| 7 | Locked | 256QAM | 423000000 Hz | 8.0 dBmV | 43.4 dB | 335 | 342 |
| 8 | Locked | 256QAM | 429000000 Hz | 8.2 dBmV | 44.6 dB | 323 | 315 |
| 9 | Locked | 256QAM | 435000000 Hz | 8.5 dBmV | 43.4 dB | 258 | 342 |
| 10 | Locked | 256QAM | 441000000 Hz | 8.5 dBmV | 43.4 dB | 343 | 1272 |
| 11 | Locked | 256QAM | 447000000 Hz | 8.6 dBmV | 43.4 dB | 413 | 2132 |
| 13 | Locked | 256QAM | 459000000 Hz | 9.0 dBmV | 43.4 dB | 243 | 320 |
| 14 | Locked | 256QAM | 465000000 Hz | 9.0 dBmV | 43.4 dB | 389 | 2449 |
| 15 | Locked | 256QAM | 471000000 Hz | 9.0 dBmV | 43.4 dB | 240 | 358 |
| 16 | Locked | 256QAM | 477000000 Hz | 9.0 dBmV | 43.4 dB | 272 | 324 |
| 17 | Locked | 256QAM | 483000000 Hz | 9.1 dBmV | 43.4 dB | 246 | 311 |
| 18 | Locked | 256QAM | 489000000 Hz | 9.1 dBmV | 43.4 dB | 352 | 1349 |
| 19 | Locked | 256QAM | 495000000 Hz | 9.0 dBmV | 43.4 dB | 322 | 1236 |
| 21 | Locked | 256QAM | 507000000 Hz | 8.6 dBmV | 43.4 dB | 274 | 1359 |
| 22 | Locked | 256QAM | 513000000 Hz | 8.6 dBmV | 40.9 dB | 372 | 2403 |
| 23 | Locked | 256QAM | 519000000 Hz | 8.5 dBmV | 43.4 dB | 346 | 1317 |
| 24 | Locked | 256QAM | 525000000 Hz | 8.4 dBmV | 43.4 dB | 149 | 381 |
| 25 | Locked | 256QAM | 531000000 Hz | 8.1 dBmV | 43.4 dB | 448 | 2319 |
| 26 | Locked | 256QAM | 537000000 Hz | 7.8 dBmV | 40.9 dB | 231 | 265 |
| 27 | Locked | 256QAM | 543000000 Hz | 7.6 dBmV | 43.4 dB | 937 | 2811 |
| 29 | Locked | 256QAM | 555000000 Hz | 7.1 dBmV | 40.9 dB | 236 | 1270 |
| 30 | Locked | 256QAM | 561000000 Hz | 7.0 dBmV | 43.4 dB | 371 | 2175 |
| 31 | Locked | 256QAM | 567000000 Hz | 7.4 dBmV | 43.4 dB | 269 | 1320 |
| 32 | Locked | 256QAM | 573000000 Hz | 7.4 dBmV | 40.9 dB | 545 | 2274 |
| 193 | Locked | OFDM PLC | 722000000 Hz | 6.7 dBmV | 44.0 dB | 7230466 | 915 |
| 194 | Locked | OFDM PLC | 957000000 Hz | -2.9 dBmV | 39.0 dB | 37156719 | 124 |
| Upstream Bonded Channels | ||||||
|---|---|---|---|---|---|---|
| Channel ID | Lock Status | US Channel Type | Frequency | Width | Power | |
| 4 | Locked | SC-QAM | 35600000 Hz | 6400000 | 45.5 dBmV | |
| 1 | Locked | SC-QAM | 16400000 Hz | 6400000 | 45.3 dBmV | |
| 3 | Locked | SC-QAM | 29200000 Hz | 6400000 | 45.3 dBmV | |
| 2 | Locked | SC-QAM | 22800000 Hz | 6400000 | 45.3 dBmV | |
| 41 | Locked | OFDMA | 36200000 Hz | 44400000 | 42.0 dBmV | |
Current System Time:08/30/2025 19:52:51
Can someone please reach out to me and assist me? I really don't want to have to abandon Xfinity and go suffer with Lumen/CTL since they're the only other landline option, but I really need stable internet in order to enjoy my free time and work from home.
Accepted Solution
user_jrs4
Visitor
•
2 Messages
4 hours ago
Hi all - follow up.
I was able to schedule a second technician for a site visit, and this tech checked both the service at my demarcation box in the garage but also the tap in the pedestal at the street. He identified that the tap was outdated and antiquated, and called for a replacement. It was replaced, and I have had proper service since.
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XfinityJustinM
Official Employee
•
303 Messages
14 days ago
Hi @user_jrs4, thank you for taking the time to detail your recent experience. It sounds like you've already done plenty of basic troubleshooting, and we'll need to take a closer look at things to locate the pain point. If you could send our team a direct message with your full name, the name listed on the account (if different), and the service address associated with your account, I'd be more than happy to look into this for you.
To send a "Direct Message" to Xfinity Support:
Click "Sign In" if necessary
Click the "Direct Messaging" icon
Click the "New message" (pencil and paper) icon
The "To:" line prompts you to "Type the name of a person". Instead, type "Xfinity Support" there
- As you are typing a drop-down list appears. Select "Xfinity Support" from that list
- An "Xfinity Support" graphic replaces the "To:" line
Type your message in the text area near the bottom of the window
Press Enter to send it.
(edited)
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